The present invention relates generally to computers and other electronic assemblies comprising printed circuit boards, and more particularly, to apparatus for affixing printed circuit boards within computer and other electronic assemblies. Still more particularly, the present invention relates to a printed circuit board fastener that, with only minor effort, may be positioned anywhere within the chassis of a computer and another electronic assembly.
Computer and other electronic assemblies typically include one or more printed circuit (PC) boards that support electronic components. Commonly, PC boards are secured within a steel or plastic chassis for an electronic assembly by means of screws extending through holes in the PC board and threadedly engaged to a portion of the chassis.
Although this manner of attachment is reliable, it has several disadvantages. First, installation of a PC board by means of screws is a very labor-intensive operation. Holes must be bored in the PC board. Corresponding female-threaded holes or receptacles must be installed in the chassis. The PC board must be aligned in the proper position, and the screws must be rotated into place. In addition, the screws and other materials are relatively costly, and the chassis, having been adapted to receive a particular size PC board, is not readily adaptable to PC boards of other sizes.
The assignee of the present invention has used an alternative PC board mounting technique by which vertically-extending plastic hooks are molded into the base of a plastic chassis. The hooks are received through slots formed in a PC board as the PC board, lying in a horizontal plane, is lowered onto the base of the chassis. After the PC board is seated on the chassis, with hooks extending through slots, the PC board is displaced horizontally to engage the hooks on the upper surface of the PC board at one end of the slots, thereby preventing vertical motion of the PC board. Thereafter, a small plastic catch mechanism is snapped into engagement with an edge of the PC board to prevent horizontal motion.
Like the method of attachment that relies on screws, the latter method of attachment works well, but is limited to a particular size of PC board for which the chassis has been especially adapted.
Manufacturers of computer and other electronic apparatus constantly improve their products. These improvements frequently include the addition of greater computing capacity and features in ever smaller and lighter weight packages. As a result, computer manufacturers constantly face the problem of repackaging PC boards of different, usually smaller, sizes. Designing and manufacturing a new chassis mold is a significant expense, particularly if it must be done each time a new PC board is designed. With a PC board mounting technique that depends upon features molded into the chassis base, such as hooks or receptacles for screws, the manufacturer has no alternative but to absorb the expense and redesign the chassis.
Hence, it would be advantageous to devise a PC board mounting apparatus that is relatively inexpensive, as well as easy to install and de-install, and that can be positioned anywhere within the chassis without significant mechanical modification, thereby enabling the chassis to accommodate PC boards of a variety of sizes without redesign of the chassis.